There are needs for classifying a plurality of pages included in an image file into predetermined groups (for example, titles) and thus easily searching the respective groups. Regarding this, an image processing apparatus has been suggested in which additional information is attached to a specific page of a plurality of pages included in an image file, and the specific page can be easily searched by searching the additional information. For example, according to an apparatus disclosed in related-art, a bookmark image is attached on an image of the specific page as the additional information. The apparatus searches the bookmark image to easily search the specific page. Also, according to the related-art apparatus, a user divides an original document into predetermined groups and attaches the bookmark image on each leading page. The apparatus reads each page having the bookmark image attached thereon together with the other pages, and thus, an image file including the page having the bookmark image attached thereon is generated.
When preparing the image file by using the above-described apparatus, it is necessary for the user to attach the bookmark image on the original document. Accordingly, when the number of pages on which the bookmark should be attached becomes large, a quantity of work for attaching the bookmark image also increases, an that it becomes inconvenient for the user.